Description

Mercury / MerCruiser Quicksilver Spark Plug Wire Set — 863656A1

The Mercury Quicksilver 863656A1 Spark Plug Wire Set is a genuine OEM ignition wire kit designed for MerCruiser V8 MPI sterndrive and inboard engines equipped with ECM-controlled ignition systems. The set delivers high-voltage current from the ignition coil and distributor to the spark plugs, ensuring reliable ignition and smooth engine performance.

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Key Specifications

• Part Number: 863656A1

• Mercury Format: 84-863656A1

• Component Type: Spark plug ignition wire set

• Includes: 8 spark plug wires + 1 ignition coil wire

• OEM Brand: Mercury Marine / Quicksilver

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Compatible Engines / Applications

Commonly used on MerCruiser V8 MPI gasoline engines with ECM-controlled ignition, including:

• 5.0L MPI (305 CID)

• 5.7L MPI / 350 MAG

• 6.2L MPI

• 377 MAG MPI

• 383 MAG Stroker

Typically used on MerCruiser sterndrive and inboard engines from approximately 2001–2015 with ECM 555 ignition systems.

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Function

The spark plug wire set transfers high-voltage ignition energy from the ignition coil and distributor to each spark plug in the correct firing order. Properly functioning wires ensure:

• Strong and consistent spark delivery

• Smooth engine starting and idle

• Reliable engine performance under load

The wires are manufactured with marine-grade insulation to withstand heat, vibration, and moisture common in marine engine environments.

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Symptoms of Worn Spark Plug Wires

A worn or damaged wire set may cause:

• Engine misfires

• Rough idle or hesitation

• Hard starting

• Poor fuel economy

Replacing the wire set helps restore proper ignition performance.

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Fitment Tip:
Always verify compatibility using the engine model and serial number. MerCruiser MPI engines may use different ignition wire sets depending on the ignition system and distributor style installed.

OEM parts ship same or next day for fast Canada wide shipping.

Technical Specifications:

• Type: Spark plug wire set
• Compatible with: Mercury MerCruiser marine engines
• Part Number: 863656A1